December 15, 1910] 



NATURE 



227 



graphs. Fifth paper : Results of the measurement of two 

 Yerkes negatives. The negatives, taken by Prof. Ritchey, 

 were extremely fine, but their dates — given as 1901 

 August 3 and November 21 — were uncertain. The result 

 of the author's reduction of the measures of the plates 

 enabled him to show that they were actually taken on 

 September 3 and November 20. The measures appeared 

 to show that points on the moon greatly above or below 

 the mean surface should be rejected, owing to their being 

 shifted in opposite directions by libration. A diagram was 

 drawn to exhibit the close agreement between points in- 

 dependently measured on phot<^raphs by Prof. Franz and 

 Mr. Saunder compared with the considerable divergence in 

 the positions of the same points as determined by Lohr- 

 mann and Madler. The actual measures had been made 

 on the negatives by Mr. Hardcastle. 



Paris. 



Academy of Sciences, December 3. — M. Emile Picard in 

 the chair. — G. Lippmann : Two pieces of metal lightly 

 touching do not, in general, form an electrical contact 

 when the difference of potential is small. Two forms of 

 contact are described in which no pressure is necessary. 



V, In one of these a strip of paper moistened with a solu- 

 tion of an electrolyte {calcium chloride) is employed ; the 

 second consists of two amalgamated silver wires. — A. 

 Gautier : Concerning the invention of porous filtering 

 candles. The author fwints out that he described the 

 manufacture and use of porous porcelain filters two years 

 before Ch. Chamberland. — A. Laveran and A. Pettit : 

 A new haemogregarian of Damonia subtrijuga. — M. 

 Gouy : The potential of the discharge in a magnetic field. 

 — W. Kilian and M. Gig^noux : The levels of the pebble 

 beds and terraces in the neighbourhood of Saint-Rambert- 

 d'Albon (Dr6me) and of Beaurepaire (Is^re). — M. 

 I^ecornu was elected a member in the section of mechanics 

 in the place of the late M. Maurice Levy. — G. D. 

 Boerlagre : An attempt at " vol a vortex." Attention 

 is directed to the effect of the thickness of the front edge 

 of the wing in birds, and the author suggests that an 

 attempt might be made to realise these conditions in aero- 

 planes. — M. Lambert : A form of the equations of motion 

 of a small planet. — M. Borrelly : Observations of the new 

 Cerulli comet made at the Observatory of Marseilles with 

 the comet finder. Data are given for November 10, 12, 

 14, and 16. — M. Cogrgria : Observations of the Faye comet 

 (igioe, Cerulli, November 9) made at the Observatory of 

 Marseilles with the Eichens equatorial of 26-cm. aperture. 

 Positions are given for November 12 and 16. — P. E. 

 Gau : The integration, by the method of M. Darboux, of 

 any partial differential equation of the second order. — T. 

 Lalesco : The poles of resolving nuclei. — Henri Villat : 

 The movements of a fluid round an obstacle of given form. 

 — Marcel Chopin : The absolute measurement of currents 

 of great intensity. A description of a modified tangent 

 galvanometer capable of measuring currents up to 1000 

 amperes. — M. Tian : The nature of the decomposition of 

 hydrogen peroxide solutions produced by light. It has 

 been shown that the decompwsition of hydrogen peroxide 

 by heat is a bimolecular reaction, whilst the decomposi- 

 tion by catalysis in presence of colloidal platinum, diastase, 

 &x., is a unimolecular reaction. An experimental study 

 of the decomposition produced by ultra-violet light shows 

 that the reaction is unimolecular, and hence is not 

 analogous to the action of heat, but rather resembles 

 catalytic decomposition. — Paul Jggrou : The reception of 

 the Hertzian time signal from the Eiffel Tower. The 

 apparatus described and illustrated works with Leclanche 

 cells instead of secondary batteries, and is simplified in 

 other directions. — L. Decombe : The mechanical inter- 

 pretation of the principle of Carnot and Clausius. The 

 case of a compensated transformation. — F. Charron : The 

 modifications produced by the air layer in friction and 

 sliding between solid bodies. — Br. Glatzel : New experi- 



, nients in stimulation by shocks in wireless telegraphy. It 

 IS well known that by interposing very short sparks into 

 the primar>- circuit of a Hertzian wave excitor the vibra- 

 tions in this circuit are effectually deadened. The author 

 passes the sparks through a tube containing hvdrogen 

 between nickel electrodes. Reoroductions of photographs 

 NO. 2146, VOL. 85] 



are given showing the complete damping effect obtained. 

 — R. Marcelin : The mechanics of irreversible pheno- 

 mena. — A. BesBon and L. Fournier : By passing a 

 rapid current of hydrogen bromide over amorphous silicon 

 at a red heat a liquid is obtained which, on submitting 

 to fractional distillation, gives as the main product of the 

 reaction silicon tetrabromide ; small quantities of 

 SiHjBr, are also obtained, and also a liquid which appears 

 to be a mixture of this with SiHjBr. Details are also 

 given of a rapid method of preparing a crude silicon suit- 

 able for the reaction. By the action of the silent dis- 

 charge upon the vapours of the silicobromoform four sub- 

 stances were identified, SiBr^, Si^Br,, Si^Br,, and 

 Si^Br,o, the silicon analogues of tetrabromomethane, 

 octobrompropane, and decabrombutane. — E. A. Salmon : 

 A method for producing a reaction between two bodies in 

 the electric arc. — L. Tchousraeff and W. Fomin : The 

 addition of hydrogen to the isomeric thujenes and 

 sabinene. The application of the Sabatier and Senderens 

 reactions having been shown to be too energetic in the 

 case of these two hydrocarbons, the addition of two atoms 

 of hydrogen to each molecule was effected by the cata- 

 lytic action of platinum black, the hydrogen being used 

 under a pressure of 25 to 50 atmospheres. The physical 

 and chemical properties of the resulting hydrocarbons are 

 given. — Georges Denig:6s : A new reaction of morphine. 

 The reagent proposed is a mixture of ammonia, hydrogen 

 peroxide, and copper sulphate in aqueous solution. A 

 red colour is produced if the concentration of the morphine 

 is above 003 gram per litre. This reaction gives negative 

 results with codeine, thebaine, papaverine, narceine, and 

 narcotine. — A. Verneuil : The nature of the oxides causing 

 the coloration of the Oriental sapphire. Careful analyses 

 of sapphires from different sources (Montana, Burmah, 

 and .Australia) showed the invariable constituents to be 

 oxide of iron and oxide of titanium. The latter oxide 

 was not detected in the earlier analyses by other workers. 

 No chromium was found in the two sapphires examined 

 for this element, and the author concludes that chromium 

 is not essential to the production of the characteristic 

 colour. The conclusion that the colour is due to the 

 oxides of titanium and iron alone is confirmed by the 

 synthesis of the gem by fusion previously described. — 

 Henri Coupin : The influence of various volatile sub- 

 stances on the higher plants. — L. Moreau and E. Vinet : 

 Insecticide treatments in viticulture. — Ed. Griffon : The 

 influence of the tarring of roads on the adjacent vegeta- 

 I tion. The author comes to the conclusion that no in- 

 i jurious effect to vegetation can be proved to have been 

 I caused by the tarring of roads. Laboratory results cannot 

 be regarded as conclusive on this point, which can only 

 be settled by actual practice in the open air. — MM. 

 Melchissedec and Frossard : Muscular fatigue in sing- 

 ing. — M. Doyon : The formation of antirhombine in the 

 liver previously frozen at a very low temperature. — G. 

 Linossier : The influence of iron on the formation of the 

 spores of Aspergillus niger. It has been shown by previous 

 workers that if iron be omitted from the culture solutions 

 of Aspergillus niger spores are not formed. The author 

 has extracted the black pigment from the spores of this 

 mould, and shows that it possesses properties resembling 

 the haematin of the blood, and contains iron as an 

 essential constituent. This furnishes a full explanation of 

 the impossibility of producing spores in the absence of 

 iron. — Gabriel Bertrand and Arthur Compton : The 

 influence of temperature on the activitv* of cellase. 

 Cellase from sweet almonds has a maximum activity at a 

 temperature of 46° C. This is independent of the duration 

 of heating, and is a specific value of great interest. — M. 

 Lemoine : The presence of deposits of cholesterol in the 

 coats of sclero-aetheromatous arteries. — Ch. Veiain and 

 -Albert Michel-L6vy : The primary strata of the south of 

 the Vosges. — MM. Bernard and IMougrin : The stratifi- 

 cation of the nive and of the ice in the upper regions of 

 the collecting areas of glacier---. — Ph. Glangreaud : The 

 glacial phenomena in the mcuntains of Forez. — Paul 

 Bertrand : General characters of the stipes of Astero- 

 chlaena laxa. — M. Martel : The removal of obstruction 

 in water-bearing fissures. — P. Mercanton : The magnetic 

 condition of the diabases of Isfjord at Spitsbergen. — 

 Louis Gentil : The lower Mlouva (eastern Morocco). 



